Single-Cell Transcriptome Analysis Revealed Heterogeneity of Fibroblast and Cellular Senescence in Aging Penile Corpus Cavernosum

Abstract

Background: The penile corpus cavernosum is a critical tissue, serving as a prerequisite for maintaining normal erection during sexual intercourse. The pathological changes of penile corpus cavernosum are significantly associated with erectile dysfunction (ED), whose prevalence increases pronouncedly with age. However, the cellular composition and molecular changes of penile corpus cavernosum during aging remain unclear. Methods: To map the single-cell transcriptomic landscape of penile corpus cavernosum during aging, we performed uniform manifold approximation and projection (UMAP), differential gene expression analysis (DGEs), pseudotime analysis and single-cell entropy algorithm to dissect cellular composition and transcriptional heterogeneity. For validation analysis, we further performed immunofluorescence studies on key molecules involved during penile corpus cavernosum aging. Findings: Clustering analysis of cell-type specific gene expression identified 19 cell types, and revealed their transcriptional alterations, which exhibited distinct properties rather than universally consistent. DGEs analysis demonstrated that genes related to extracellular matrix organization were highly expressed. Among these cell types, fibroblasts showed apparent heterogeneity. By performing pseudotime and single-cell entropy analysis on fibroblasts, we observed the age-associated decrease of entropy, and aged fibroblasts were found to adopt senescent secretory phenotype, as evidenced by the high expression of genes associated with the senescence-associated secretory phenotype (SASP). Since eliminating senescent cells or SASP were demonstrated to improve health and life span, we further investigated the distinct senescence-related gene expression signatures across all cell types during aging. Interpretation: Overall, we plotted a cellular atlas of penile corpus cavernosum, and revealed the molecular alterations of aging cells, especially fibroblasts. Our work will deepen the understanding of the heterogeneity among certain cell types during penile corpus cavernosum aging, which will generate positive effects on the future treatment of aging-related penile disorders. Funding Statement: This work was funded by the National Natural Science Foundation of China (81771573). Declaration of Interests: None declared. Ethics Approval Statement: All experimental procedures were approved by the Committee of Animal Care and Use at Sun Yat-sen University.